Chemical mechanical polishing platform architecture

ABSTRACT

Embodiments of the invention provide polishing systems for increasing production efficiency, maximizing substrate throughput, and reducing production costs. The polishing systems generally include one or more polishing stations for performing a CMP process and one or more cleaning stations at which post-polishing cleaning is performed. The number of cleaning stations and polishing heads present may be increased depending on the desired substrate throughput or processing time at each polishing station. The number of polishing stations or cleaning stations can also be reduced in order to reduce the footprint of the polishing system. The polishing pads at each polishing station can be adjusted in size to accommodate one or more polishing heads simultaneously depending on substrate throughput and system footprint. Additionally, the polishing pads may be replaced with a fixed abrasive pad, or adapted to polish 450 millimeter substrates.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to methods and apparatus for chemical mechanical polishing (CMP) of substrates.

2. Description of the Related Art

CMP is a known process used to planarize one or more surfaces of a substrate. Although many commercially available CMP systems have demonstrated robust polishing performance, the move to smaller line widths requiring more precise fabrication techniques, along with a continued need for increased throughput, drives an ongoing effort for polishing system improvements. As fabrication techniques continue to improve, CMP platform architecture must adapt to not only utilize the techniques, but to also polish substrates in an efficient and cost effective manner. Since fabrication techniques are constantly changing, and the variety of substrates to be processed is constantly increasing, existing CMP platform architectures may not be the most efficient tools for processing substrates.

Therefore, there is a need for new CMP platform architectures for processing substrates.

SUMMARY OF THE INVENTION

Embodiments of the invention provide polishing systems for increasing production efficiency, maximizing substrate throughput, and reducing production costs. The polishing systems generally include one or more polishing stations for performing a CMP process and one or more cleaning stations at which post-polishing cleaning is performed. The number of cleaning stations and polishing heads present may be increased depending on the desired substrate throughput or processing time at each polishing station. The number of polishing stations or cleaning stations can also be reduced in order to reduce the footprint of the polishing system. The polishing pads at each polishing station can be adjusted in size to accommodate one or more polishing heads simultaneously depending on substrate throughput and system footprint. Additionally, the polishing pads may be replaced with a fixed abrasive pad, or adapted to polish 450 millimeter substrates.

In one embodiment, a polishing system comprises a polishing module having at least three polishing stations and a circular track disposed above the at least three polishing stations. At least six polishing heads are coupled to the circular track. The polishing system further comprises a cleaning module in operable communication with the polishing module. The cleaning module has two cleaning stations and a central transfer area disposed between the two cleaning stations. The central transfer area is in operable communication with a factory interface. Each of the two cleaning stations are separated from the central transfer area by a wall.

In another embodiment, a polishing system comprises a polishing module having at least three polishing stations and a circular track disposed over the at least three polishing stations. Each polishing station has a polishing pad adapted to polish one substrate thereon. The polishing system further comprises a cleaning module having a central transfer area and a cleaning module. The central transfer area is separated from the cleaning module by a wall.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIGS. 1A-1G are top plan views of polishing systems according to embodiments of the invention.

FIG. 2 is a perspective view of a polishing station according to one embodiment of the invention.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

DETAILED DESCRIPTION

Embodiments of the invention provide polishing systems for increasing production efficiency, maximizing substrate throughput, and reducing production costs. The polishing systems generally include one or more polishing stations for performing a CMP process and one or more cleaning stations at which post-polishing cleaning is performed. The number of cleaning stations and polishing heads present may be increased depending on the desired substrate throughput or processing time at each polishing station. The number of polishing stations or cleaning stations can also be reduced in order to reduce the footprint of the polishing system. The polishing pads at each polishing station can be adjusted in size to accommodate one or more polishing heads simultaneously depending on desired substrate throughput and system footprint. Additionally, the polishing pads may be replaced with a fixed abrasive pad, or adapted to polish 450 millimeter substrates.

FIGS. 1A-1E are top plan views of polishing systems according to embodiments of the invention. FIG. 1A illustrates a polishing system 100A. The polishing system 100A includes a polishing module 101A, a cleaning module 102A, and a factory interface 103. The factory interface 103 includes a robot 104 disposed on an optional track 105. The robot 104 is adapted to remove a substrate 106 from one of the substrate storage cassettes 107 and transfer the substrate 106 to transfer platforms 180 through a port 110, such as a slit valve. The robot 104 is also configured to receive substrates from each cleaning station 109A, 109B through vertically-actuating ports 111 subsequent to a cleaning process and return the cleaned substrates to the substrate storage cassettes 107. The ports 111 are shown as having an “L” shape; however, other shapes, such as linear, are contemplated. The use of an L-shaped port 111 allows for egress of substrates from the polishing stations 109A, 109B through a port having a smaller width, thus allowing the foot print of the cleaning stations 109A, 109B to be reduced. The port widths are reduced due to the port openings wrapping around the corner of the polishing stations 109A, 109B, thereby reducing the width of the ports 111 in any one direction. In contrast, if the ports 111 were disposed on a single wall instead of having an L-shape, the width of the ports 111 may need to be increased to accommodate the passage of substrates therethrough. The increased width of the ports 111 may require that the width of the cleaning stations 109A, 109B be increased to accommodate the ports 111, which in turn would increase the footprint of the cleaning stations 109A, 109B.

The factory interface 103 is positioned adjacent to and in operable communication with the cleaning module 102A. The cleaning module 102A includes two cleaning stations 109A, 109B, a central transfer area 112 located therebetween, and a shuttle trough 113 positioned at one end of the cleaning module 102A opposite the factory interface 103. The utilization of two separate cleaning stations 109A, 109B allows for one of the cleaning stations 109A, 109B to be shut down for maintenance, while the other cleaning station continues to process substrates. Thus, throughput is merely reduced, and not halted, when cleaning or maintenance of one of the cleaning stations 109A, 109B is desired. Additionally, separation of the cleaning stations 109A, 109B reduces the probability of cross-contamination within the cleaning stations 109A, 109B. For example, if different polishing processes are being performed at different polishing stations 128A within the polishing module 101A, then each of the cleaning stations 109A, 109B may be dedicated to cleaning substrates coming from selected polishing stations 128A. In this manner, a unique cleaning process may be matched with a specific polishing process so that the cleaning stations 109A, 109B cannot be contaminated with substrates processed in a polishing station 128A running a different polishing process.

The cleaning stations 109A, 109B are separated from the central transfer area 112 by walls 117. The wall 117 facilitates environmental isolation between the central transfer area 112 and each of the cleaning stations 109A, 109B. The cleaning stations 109A, 109B and the central transfer area 112 are in communication with one another through the shuttle trough 113, which may be selectively partitioned further facilitate environmental isolation between the central transfer area 112 and each of the cleaning stations 109A, 109B. Each cleaning station 109A, 109B includes a plurality of cleaning units 115 and a dryer 120, each of which generally includes an opening formed in the upper portion thereof for accepting substrates therein. The cleaning units 115 may be one or more of brush boxes, rinsing stations, spray jet units, megasonic cleaners, or combinations of two or more thereof. Robots 116 a, 116 b are each connected to a track disposed in each of the cleaning stations 109A, 109B and coupled to a surface of the walls 117. The robots 116 a, 116 b are adapted to move a substrate received from the shuttle trough 113 through each of the cleaning units 115 to the dryer 120. The dryer 120 has an output station (not shown) through which the substrate is presented for transfer to the robot 104, which then stores the substrate in the substrate storage cassettes 107. For example, a first robot 116 a may be adapted to move substrates through a first set of cleaning units 115, such as the first two cleaning units 115, while a second robot 116 b may be adapted to move the substrate through a second set of cleaning units 115 and the dryer 120. The use of two robots 116 a, 116 b minimizes cross-contamination between the cleaning units 115 and the dryer 120 while improving throughput.

The central transfer area 112 of the cleaning module 102A is in communication with the factory interface 103 and the polishing module 101A through ports 110 and 118, respectively, each of which may be independently opened and closed. The central transfer area 112 includes two transfer platforms 180 to facilitate transfer of substrates, two buffer stations 108A, 108B and a robot 119 adapted to transfer substrates from the transfer platforms 180 to the interior of the polishing module 101A through the ports 118. One or more substrates may optionally be vertically positioned in the buffer stations 108A, 108B, which contain a solution such as deionized water, to mitigate process delays due to robot transfer times, or to store substrates therein during tool faults or process delays. In such an embodiment, the robot 119 may remove substrates from the buffer stations 108A, 108B as needed. Storing substrates vertically allows for more substrates to be stored in a smaller area, thereby reducing the footprint of the central transfer area 112. The robot 119 includes a linkage assembly 124 coupled to an overhead track or linkage (not shown), a robot body 127 coupled to the linkage assembly 124, and two end effectors 126 coupled to the robot body 127. The robot 119 is adapted to remove substrates from the transfer platforms 180 and transfer the substrates into the polishing module 101A to load cups 121A and 121B through the port 118. The robot 119 is also adapted to remove substrates from the load cups 121A and 121B after a polishing process, and dispose the substrates in the shuttle trough 113 through an opening 125 located in the upper surface of the shuttle trough 113. The end effectors 126 each generally include at least one gripping device, such as a mechanical clamp or suction device, in order to secure substrates thereto.

The shuttle trough 113 accepts substrates in a vertical orientation for placement on shuttles 138 located therein. The shuttles 138 then transfer the substrates to a location proximate the cleaning stations. 109A, 109B (i.e., adjacent to openings 137) to facilitate transfer of the substrates to the robots 116 a. The robot 119 is adapted to pivot at the connection between the robot body 127 and the linkage assembly 124 to allow the end effectors 126 to assume a vertical orientation for transfer of polished substrates through the opening 125 located in the shuttle trough 113.

The polishing module 101A includes a plurality of polishing stations 128A on which substrates are polished on polishing pads 135 while retained in polishing heads 131. In the embodiment of FIG. 1A, three polishing stations 128A are shown, however, it is contemplated that more or less polishing stations 128A may be utilized. The polishing stations 128A are sized to interface with at least one polishing head 131 so that at least one substrate may be polished in the polishing station 128A. In the embodiment depicted in FIG. 1A, the polishing stations 128A are sized to interface with at least two polishing heads 131 simultaneously so that polishing of multiple substrates at the same polishing station 128A may occur at the same time. Six polishing heads 131 are shown, but it is contemplated that the polishing module 101A may include two additional polishing heads 131, which are shown in phantom. Each polishing station 128A includes one or more pad conditioners 134 for conditioning an upper surface of the polishing pad 135, and one or more fluid delivery arms 136 for delivering a polishing fluid, such as a polishing slurry or rinse fluid, to the upper surface of the polishing pad 135. In the embodiment depicted in FIG. 1A, each polishing station 128A includes at least two pad conditioners 134 and at least two fluid delivery arms 136.

The polishing heads 131 are coupled to carriages that are mounted to an overhead track 130 (shown in phantom) having a curved shape. The overhead track 130 allows the polishing heads 131 to be selectively positioned around the polishing module 101A including over the polishing pads 135 disposed in the polishing stations 128A and load cups 121A and 121B. Thus, the polishing heads 131 are movable along the track 130 to a position over the load cups 121A and 121B where substrates can be engaged and retained by the polishing heads 131. The polishing heads 131 can then return to a position over a selected one of the polishing stations 128A via movement along the track 130 for polishing of the substrates on the polishing pads 135.

The above description describes the structure of the polishing system 100A; and now the movement of substrates through the polishing system 100A will be described. The robot 104 unloads substrates 106 from the substrate storage cassettes 107 and transfers the substrates to the transfer platforms 180 through the port 110. The robot 119 then engages and lifts one substrate from each of the transfer platforms 180 simultaneously. The robot rotates approximately 180 degrees and enters the polishing module 101A to position the substrates on the load cups 121A, 121B through the port 118. The robot 119 is then retracted from the polishing module 101A.

Two polishing heads 131 travel along the track 130 to a position above the load cups 121A and 121B. The polishing heads 131 actuate downward to engage and secure a substrate from each of the load cups 121A and 121B. The polishing heads 131 then lift upward to provide sufficient clearance of the load cups 121A and 121B, and move to a position above one of the polishing stations 128A for polishing of the secured substrates. The remaining polishing heads 131 may likewise secure substrates from the load cups 121A, 121B after substrates have been placed thereon by the robot 119. It is contemplated that each polishing station may have a different polishing process performed thereon, and thus, substrates may proceed though each polishing station in a clockwise or counterclockwise direction until returning to the load cups 121A, 121B where the substrates can then be removed from the polishing module 101A. Alternatively, similar polishing processes may be performed at each polishing station 128A, and thus, the substrates need not be polished at each polishing station 128A prior to returning to the load cups 121A, 121B.

After completion of the polishing of the substrates located in polishing heads 131, the polishing heads 131 rotate along the track to a position over the unoccupied load cups 121A, 121B, and transfer the polished substrates to the load cups 121A, 121B for removal from the polishing module 101A by the robot 119. The robot 119 removes the polished substrates from the load cups 121A, 121B and disposes the polished substrates in the opening 125 of the shuttle trough 113. Each of the polished substrates is disposed on the shuttle 138 located within the shuttle trough 113, and transferred via the shuttle 138 to one of the cleaning stations 109A, 109B. The shuttles 138 are independently operable to allow a first shuttle 138 to carry a first substrate to the cleaning station 109A, and to allow a second shuttle 138 to carry a second substrate in an opposite direction to cleaning station 109B.

The polished substrates are then removed from the shuttle trough 113 through openings 137 by respective robots 116 a, 116 b located in each of the cleaning stations 109A, 109B. A first robot 116 a in each of the cleaning stations 109A, 109B advances the polished substrate through a first set of the cleaning units 115, such as the first two cleaning units 115. A second robot 116 b in each of the cleaning stations 109A, 109B removes the substrate from the last cleaning unit 115 of the first set of cleaning units 115, and then advances the substrate through the remainder of the cleaning units 115 and the dryer 120. The cleaned substrates are then removed from the cleaning stations 109A, 109B by the robot 104 and stored in the substrate storage cassettes 107. The use of two robots 116 a, 116 b minimizes cross-contamination between the cleaning units 115 and the dryer 120 while improving throughput.

The polishing system 100A illustrated in FIG. 1A allows for process flexibility, including environmentally isolated and dedicated cleaning stations for selective polishing stations 128A. Furthermore, the polishing system 100A utilizes a reduced footprint to reduce the amount of fabrication space required to process substrates, thereby reducing the unit cost of manufactured devices.

FIG. 1B illustrates a polishing system 100B having a polishing module 101B according to another embodiment of the invention. In the embodiment shown in FIG. 1B, a polishing station 128B includes a fixed abrasive pad 122. Thus, the polishing module 101B includes two polishing stations 128A having polishing pads 135, and a polishing station 128B having a fixed abrasive pad 122. Fixed abrasive pads generally include a plurality of abrasive elements disposed on a flexible backing. In one example, the abrasive elements may comprise geometric shapes formed from abrasive particles, such as ceria, suspended in a polymer binder. Fixed abrasive pads generally facilitate polishing of substrates in a manner similar to the polishing pads 135, however, fixed abrasive pads are often utilized in combination with a polishing fluid which does not contain any additional abrasive particles therein. Although the polishing station 128B is shown has having one fluid delivery arm 136, it is contemplated that the polishing station 128B may contain a plurality of fluid delivery arms 136.

The combination of the fixed abrasive pad 122 along with the polishing pads 135 increases process flexibility of the polishing system 100B. For example, fixed abrasive polishing pads may be more efficient at polishing specific materials, or may be more beneficial for bulk removal steps. Thus, the combination of the fixed abrasive pad 122 and the polishing pads 135 may allow for more efficient polishing of substrates, thereby increasing throughput and reducing production costs. It should be noted that although the fixed abrasive pad 122 is positioned between two polishing pads 135 in the embodiment illustrated in FIG. 1B, it is contemplated that the fixed abrasive pad 122 may not be positioned between the two polishing pads 135. Thus, the fixed abrasive pad 122 may be positioned before or after the two polishing pads 135 with respect to the rotation of the polishing heads 131 along the track 130.

FIG. 1C illustrates a polishing system 100C having a polishing module 101C, a cleaning module 102C, and a factory interface 103. The polishing module 101C is similar to polishing module 101A (shown in FIG. 1A), except that each polishing station 128C is adapted to have only one polishing head 131 disposed thereover. Therefore, polishing of only a single substrate at a time occurs at each polishing station 128C. It is contemplated that the polishing module 101A can be converted to the polishing module 101C at fabrication locations, thereby providing process flexibility. Because only a single substrate is processed at a polishing station 128C at any given time, the size (e.g., footprint) of the polishing station 128C can be reduced. Reduction in size of the polishing stations 128C allows for a reduction of size in the polishing module 101C, thereby reducing the total footprint of the polishing system 100C. Reduction in footprint reduces production costs, because fabrication space is often one of the most expensive costs when fabricating devices.

The polishing system 100C also includes a cleaning module 102C. The cleaning module 102C is similar to the cleaning module 102A (shown in FIG. 1A), except that the cleaning module 102C contains only a single cleaning station 109A. Since each polishing station 128C in the polishing module 101C is adapted to polish only a single substrate at a time, only a single cleaner is necessary to clean the polished wafers transferred from the polishing module 101C. Since only a single cleaning station 109A is utilized, the footprint of the polishing system 100C can be further reduced, thereby further decreasing the production cost of devices manufactured using the polishing system 100C. Additionally, it is contemplated that the central transfer area 112 may contain only a single buffer station 108A or 108B, as well as a single transfer platform 180, thereby further reducing the footprint of the polishing system 100C.

FIG. 1D illustrates a polishing system 100D having a polishing module 101D, and cleaning module 102C, and a factory interface 103. The polishing module 101D is similar to the polishing module 101C (shown in FIG. 10), except that the polishing module 101D includes four polishing stations 128A. Four polishing stations 128A may be particularly beneficial for increasing substrate throughput, especially in circumstances where at least some of the polishing stations 128A perform similar polishing processes. For example, four polishing stations may be beneficial when the polishing time at one of the polishing stations 128A exceeds the polishing time at the remaining polishing stations 128A, and thus, it may be desirable to have multiple polishing stations 128A performing the slowest of the polishing processes which occur on the polishing system 100D.

FIG. 1E illustrates a polishing system 100E adapted to polish 450 millimeter substrates. The polishing system 100E includes a polishing module 101E, a cleaning module 102E, and a factory interface 103. The polishing module 101E is similar to polishing module 101C (shown in FIG. 1C), except that the sizes of the polishing heads 131 and the load cups 121A, 121B have been increased to accommodate 450 millimeter substrates. In the embodiment shown in FIG. 1E, the polishing pads 135 may have a diameter of about 30 inches or greater, such as about 30 inches to about 52 inches. While the polishing module 101E is shown as having polishing stations 128E used to a polish a single substrate at a time, it is contemplated that more than one substrate may be polished simultaneously at each polishing station 128E. In such as embodiment, however, the footprint of the polishing system 100E would be increased.

The cleaning module 102E is similar to the cleaning module 102C (shown in FIG. 10), except that the central transfer area 112 is adapted to transfer only a single substrate at a time therethrough. Thus, the central transfer area contains a single buffer station 108A, a single transfer platform 180, and a robot 119E having a linkage assembly 124 and a single end effector 126. While it is contemplated that the central transfer area 112 may be adapted to transfer multiple substrates simultaneously, the size of the central transfer area 112 would then be increased, thereby increasing the footprint of the polishing system 100E.

FIG. 1F illustrates a polishing system 100F having a polishing module 101F, a cleaning module 102C, and a factory interface 103. The polishing module 101F is similar to the polishing module 101C, however, the polishing module 101F includes six polishing stations 128C. The utilization of six polishing stations, each being adapted to polish a single substrate at a time, allows for more control of the polishing process of substrates. The additional control is especially beneficial for sensitive polishing applications. For example, the use of six polishing modules 128C allows for the polishing rate at each polishing station 128C to be reduced (thus providing more uniform polishing of substrates) while still being able to maintain the desired throughput. Since only a single substrate is polished at a polishing station 128C, polishing uniformity is further insured, as the single substrate is unaffected by a second substrate being polished at the same polishing stations 128C.

Although the polishing module 101F is shown having six polishing stations 128C, it is contemplated that the polishing module 101F may include less than six polishing stations 128C. For example, the polishing module 101F may have four polishing stations 128C or five polishing stations 128C. In embodiments where the polishing module 101F includes less than six polishing stations 128C, the position of the polishing stations 128C in the polishing module 101F may be rearranged in order to minimize the footprint of the polishing module 101F.

FIG. 1G illustrates a polishing system 100G having a polishing module 101G, a cleaning module 102E, and a front end 103. The polishing module 101G includes a first area 160A which is separated and environmentally isolated from a second area 160B by a partition 149. The partition 149 includes a housing 150 and a movable door 151 which form a seal across the polishing module 101G to separate the first area 160A from the second area 160B. The movable door 151 is adapted to be extended from the housing 150 or positioned therein to allow for communication between the first area 160A and the second area 160B as desired. Extension of the movable door 151 facilities maintenance of the first side 160A or the second side 160B while reducing the probability of cross-contamination therebetween. Alternatively, the movable door 151 may remain extended to reduce particle contamination between the first side 160A and the second side 160B during polishing. When the movable door 151 is positioned within the housing 150, the robot 119G has access to the load cups 121A, 121B, and 121C. Since the robot 119G can access the load cups 121A-121C, throughput is improved because the robot 119E is not required to transfer substrates from the load cups 121A, 121B to 121C prior to robot 119G transferring substrates from the load cup 121C to the polishing station 128G. Thus, while the movable door 151 is positioned within the housing 150, the number of substrate transferring processes is reduced.

The first area 160A of the polishing module 101G includes a polishing station 128A adapted to polish two substrates simultaneously thereon, and two load cups 121A, 121B adapted to accept substrates from the robot 119E through an opening 118A. A track 130 is positioned over the load cups 121A, 121B and the polishing station 128A and has polishing heads 131 coupled thereto to facilitate transfer of substrates from the load cups 121A, 121B to the polish station 128A. In the embodiment illustrated in FIG. 1G, the track 130 is positioned only in the first area 160A and not in the second area 160B, as transfer of substrates in the second area 160B is generally accomplished by the robot 119G.

The second area 160B includes a polishing station 128G having three edge polishers 155 adapted to polish, grind, or bevel the edges of substrates located at the polishing station 128G. The polishing station 128G is shown as having three edge polishers 155, however, it is contemplated that the polishing station 128G may be adapted to polish any number of substrates simultaneously. The polishing station 128G includes four substrate support positions 156 located on a support 157. A first substrate support position 156 does not have an edge polisher 155 positioned adjacent thereto which allows for loading or unloading of substrates thereon via the robot 119G. Once a substrate has been loaded onto the exposed substrate support position 156, the support 157 rotates in order to provide an unoccupied substrate support position 156 for loading of an additional substrate onto the support 157. After three substrates have been loaded onto the support 157, a polishing process is then performed on the substrates by the edge polishers 155. After completion of the polishing process, the support 157 continues to rotate to facilitate unloading of polished substrate and loading of unpolished substrates onto the support 157.

The second area 160B also includes the load cup 121C therein. The load cup 121C facilitates transfer of substrates from the robot 119E to the robot 119G when the movable door 151 is extended from the housing 150. With the movable door 151 in the closed position, the robot 119E can remove a polished substrate from one of the load cups 121A, 121B through the opening 118A, and then position the substrate on the load cup 121C through the opening 118B for polishing at the polishing station 128G. Thus, the areas 160A and 160B can remain environmentally isolated to reduce cross-contamination therebetween while still allowing for transfer of substrates from one area to the other. It is contemplated that substrates may first be positioned in the second side 160B and the transferred to the first side 160A, as desired.

FIG. 2 is a perspective view of a polishing station 128A according to one embodiment of the invention. The polishing station 128A includes a platen 242 having a shaft 243 coupled to a motor 244 which is adapted to rotate the shaft 243 and the platen 242 coupled thereto. The polishing pad 135 or fixed abrasive pad is disposed on the upper surface of the platen 242 and acts as a polishing surface during a chemical mechanical polishing process. A substrate is retained against the upper surface of the polishing pad 135 during polishing by each polishing heads 131. The polishing heads 131 are coupled to carriages 245 by rotatable and vertically actuatable shafts 246. The carriages 245 are coupled to the track 130 supported above the platen 242 and below a polishing module lid 247. The carriages 245 can be selectively positioned along the track 130 within the polishing module. The carriages 245 are moved along the track 130 using an actuator (not shown), such as a magnetic actuator, a gear motor, a servo motor, a linear motor or other motion control device suitable for positioning the carriages 245 along the track 130. The carriages 245 are used to position the polishing heads 131 over the load cups, to sweep the polishing heads 131 over the polishing pad 135, or to position the polishing heads 131 clear of the load cups or polishing pad 135 for maintenance.

Rotatable fluid delivery arms 136 are positioned on opposite sides of the platen 242 and are adapted to apply one or more fluids to the upper surface of the polishing pad 135. For example, the fluid delivery arms 136 may apply one or more of a polishing slurry, a polishing fluid, a rinsing solution, or a conditioning solution to the upper surface of the polishing pad 135. Rotatable pad conditioners 134 are positioned adjacent to each of the fluid delivery arms 136. The pad conditioners 134 are adapted to contact and sweep across the polishing pad 135 to condition the upper surface thereof.

Benefits of the present invention include polishing systems for CMP processes to increase efficiency and throughput while reducing production costs. The use of additional polishing heads or the polishing of multiple substrates on a single pad can increase substrate throughput. Additionally, polishing processes utilizing both a polishing pad and a fixed abrasive pad can likewise increase substrate throughput. The cost to manufacture devices can be reduced by utilizing a polishing system having a smaller footprint, thus reducing the amount of space required to manufacture the devices.

While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. 

We claim:
 1. A polishing system, comprising: a polishing module, having: a plurality of polishing stations; a circular track disposed above the plurality of polishing stations; and a plurality of polishing heads coupled to the circular track; and a cleaning module in operable communication with the polishing module, the cleaning module having two cleaning stations, and a central transfer area disposed between the two cleaning stations in operable communication with a factory interface, wherein each of the two cleaning stations include one or more cleaning units and are separated from the central transfer area by a wall.
 2. The polishing system of claim 1, wherein one of the polishing stations includes a fixed abrasive pad.
 3. The polishing system of claim 1, wherein the plurality of polishing heads is eight polishing heads.
 4. The polishing system of claim 1, wherein the cleaning module is in operable communication with the factory interface through one or more L-shaped doors.
 5. The polishing system of claim 1, wherein the central transfer area includes two buffer stations and two transfer platforms.
 6. The polishing system of claim 5, wherein the buffer stations are adapted to contain a liquid therein.
 7. The polishing system of claim 6, wherein the buffer stations are adapted to contain a plurality of substrates positioned in a vertical orientation.
 8. A polishing system, comprising: a polishing module, having: a plurality of polishing stations, each polishing station having a polishing pad adapted to polish one substrate thereon; and a circular track disposed over the plurality of polishing stations; and a cleaning module having a central transfer area and a cleaning station, wherein the central transfer area is separated from the cleaning station by a wall.
 9. The polishing system of claim 8, wherein the cleaning station is in operable communication with a factory interface through an L-shaped door.
 10. The polishing system of claim 9, further comprising a robot disposed within the factory interface, the robot adapted to transfer substrates to or receive substrates from the cleaning station via the L-shaped door, a transform platform located within the central transfer area, and one or more cassettes coupled to the factory interface.
 11. The polishing system of claim 8, wherein each polishing pad has a diameter of about 30 inches or greater and is adapted to polish a substrate having a diameter of 450 millimeters or greater.
 12. The polishing system of claim 11, further comprising a robot disposed within the central transfer area and adapted to receive substrates from a transfer platform located within the central transfer area and transfer the substrates to one or more cups positioned within the polishing module.
 13. The polishing system of claim 12, further comprising a buffer station located within the central transfer area.
 14. The polishing system of claim 13, wherein the buffer station is adapted to contain a plurality of substrates in a vertical orientation.
 15. The polishing system of claim 14, wherein the buffer station is adapted to contain a fluid therein.
 16. The polishing system of claim 8, wherein the at least three polishing stations is four polishing stations, five polishing stations, or six polishing stations.
 17. A polishing system, comprising: a polishing module, having: a plurality of polishing stations; a plurality of polishing heads; and at least one load cup; a cleaning module, having: at least one cleaning station, the at least one cleaning station including one or more cleaning units and a dryer; a transfer area coupled to the cleaning station; at least one buffer station located within the transfer area; and a first robot disposed within the transfer area, the robot adapted to transfer substrates from the at least one buffer station to the at least one load cup; and a factory interface having a second robot the therein, the second robot adapted to transfer substrates from a substrate storage cassette coupled to the factory interface to the at least one buffer station.
 18. The polishing system of claim 17, wherein the cleaning module further comprises a second cleaning station, and wherein the transfer area is positioned between the cleaning stations and separated therefrom by a wall.
 19. The polishing system of claim 18, wherein the at least one buffer station is adapted to contain a plurality of substrates in a vertical orientation, and the second robot is adapted to remove the substrates from the at least one buffer station in the vertical orientation.
 20. The polishing system of claim 18, wherein each cleaning module comprises two robots disposed therein and adapted to transfer substrates therethrough. 